This application claims priority of Chinese Application Number 01114361.4, filed Jul. 13, 2001.
1. Technical Field
The present invention relates to a normally interlocked universal differential device.
2. Description of the Prior Art
Until now, a vehicle generally performs its power transmission by using a differential mounted on the front axle or the rear axle thereof, and such vehicle can not run normally on the muddy roads due to slipping. Accordingly, the multiple-axle dive is used for overcoming the slipping. However, it may only avoid the slipping occurring in a two-wheel drive vehicle, while a vehicle can not run normally when the wheels at one side or on a diagonal line thereof slip due to insufficient road holding force. To this end, there have been provided various differentials to overcome the slipping of the wheels. However, they have a common problem that if the differential is locked, even if the vehicle can exert sufficient tractive force, but can not make a turn; if the vehicle can make a turn, it can not exert sufficient tractive force on the muddy roads, and even can not run normally.
In order to resolve the slipping of wheels, the Chinese Patent No. ZL98100725.2 disclosed a solution, which can prevent the wheels from slipping when a vehicle runs on the muddy roads. However, while the vehicle runs on the flat roads at a high speed, only front drive or rear drive can be used. The Chinese Utility Model No. ZL99208786.4 disclosed a normally interlocked universal differential device, which resolves the problems occurring in the differential operation between wheels or axles, and in the interlocking of the differential, but there is a slipping controller in its central portion, consequently, the structure is complicated and the size is big.
An object of the present invention is to resolve the above problems in the conventional differentials.
Accordingly, there is provided a normally interlocked universal differential device with simple structure, advantageous performance and small size, and also being easy to assemble.
The normally interlocked universal differential device according to the present invention comprises a central composite differential disposed in the central portion thereof and including an outer differential and an inner differential, said inner differential being fitted into the outer differential and using one pin in common to the outer differential; two side differentials connected in series to both side ends of the central composite differential respectively, each of them having a solid axle shaft, a solid axle shaft gear mounted on the solid axle shaft, a hollow axle shaft and a hollow axle shaft gear mounted on the hollow axle shaft, said two solid axle shafts passing through the corresponding hollow axle shafts and the hollow axle shaft gears at one end thereof so that the two solid axle shafts are fitted into the two hollow axle shafts and led out from the outside ends of the two side differentials respectively, and said two solid axle shafts being connected to each other at the other end thereof via the two axle shaft gears of the inner central differential, the two hollow axle shafts of said two side differentials being coupled to the wheels located on one diagonal line, and the two solid axle shafts thereof being coupled to the wheels located on another diagonal line respectively, a planetary gear of the outer central differential being meshed with ring gears provided on the cases of said two side differentials; and two power distributors having power distributing diving gears and power distributing driven gears meshed with each other respectively, said two side differentials connected in series to both side ends of the central composite differential being coupled with wheels of the vehicle via the two power distributors respectively.
The normally interlocked universal differential device according to the present invention employs a central composite differential including an outer central differential and an inner central differential fitted into the outer central differential, the central composite differential being connected in series to the two side differentials at both side ends thereof, and then connected to the two power distributors, respectively. The four output axle shafts restrict their independence each other during operation. Accordingly, regardless losing driving force to any one of the wheels, the four output axle shafts can form new differentials jointly and arbitrarily by combining the four differentials according to the requirements of driving the wheels, thus carrying out the differential operations between the wheels, the axles or the diagonal wheels. Therefore, the vehicle can run normally and make a turn safely in spite of the conditions of the road. In addition, when the vehicle run on the expressway at a high speed, four wheels thereof differentiate simultaneously and arbitrarily, circulating in power-free state, without parasitic power and influence due to the different wheel diameters. Therefore, the structure thereof is simplified greatly and the advantageous performance is ensured. Moreover, the size is reduced and assembling becomes very easy.